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With Proton having officially unveiled facelifts for the Iriz and Persona hatchback and sedan models at the beginning of last month, the B-segment duo continues to be improved, most apparently in its infotainment, looks and equipment.

Less was mentioned about the cars’ mechanical components, and how much has been done to improve them. Some will be wondering – why has Proton retained the Punch continuously variable transmission? Proton vehicle programme executive Adzrai Aziz Ibrahim offered explanations in detail through a virtual briefing.

Proton arrived at the decision to stay with the Punch CVT gearbox after having conducted plenty of study as well as taking into account market feedback, said Adzrai, in particular benchmarking Japanese B-segment cars for this purpose. The CVT is the transmission that offers the best fuel consumption for the price and segment; this is in fact adopted by most brands in the segment, he added.

While the latest Iriz and Persona facelifts were rumoured before launch to make the switch to a Hyundai four-speed torque converter automatic transmission, this was not chosen for the recently-launched cars as four forward ratios were deemed insufficient and therefore would be detrimental to fuel consumption.

This is of greater importance to cars like the Iriz and Persona, rather than outright cost, and in addition to the fact that the B-segment duo sells in far smaller numbers than the Hyundai 4AT-equipped Saga – Proton’s best-seller – of which 4,500 to 5,000 units are sold every month, therefore the cost of engineering the fitment of a new gearbox to the Iriz and Persona could not be justified.

A six-speed automatic “might be a consideration,” said Adzrai, though it would certainly be more expensive, therefore the decision was made to stick with the CVT. After a lot of discussion, Proton had found that most reservations expressed about the CVT was in terms of perceived quality.

These had originally been addressed in the 2019 facelifts, however they were not publicised. Since the introduction of the revised transmission, there has been a reduction in warranty claims of over 80%, said Adzrai, and therefore the CVT has proven to be reliable. For this reason, Proton decided to retain the Punch CVT unit, instead of developing a new gearbox which would have brought the risks of introducing new parts.

Having said that, Proton decided that the CVT should not remain completely untouched, and therefore it has been given updates to be on par with the other CVTs used in cars of this segment, said Adzrai. Of these, Proton had benchmarked the Toyota Vios and the Honda City, which also use stepless transmissions.

Refinements made to the Punch CVT is the return of the SAT (stepped automatic transmission) mode, after it was previously removed. This now returns in a more integrated form as opposed to its earlier iteration, which featured a separate button to activate its use.

This earlier version was found to be less than seamless in practice; when the SAT button was pressed, it would simulate stepped ratios and remain that way until the driver deselects it to return to conventional, stepless CVT operation. Proton had found that transmission button modes tend not to be used, and when the simulated AT mode in a stepless CVT is used, it often “does not drive as well,” noted Adzrai.

What Proton has now, then, is an adaptation of the stepped automatic mode that does away with a separate button activation, and instead uses throttle input. For throttle position of between zero to 60% or 70%, the transmission functions normally as a CVT, beyond which it goes into the ‘stepped’ mode.

This is to mitigate the “droning” noise when a CVT-equipped vehicle is taken to full throttle, as it selects the ratio to place the engine in the thick of its powerband – around 5,000 rpm to 5,500 rpm – while the rest of the driveline, and therefore vehicle speed, gradually catches up. For this reason, Proton has employed the stepped transmission mode for use during hard acceleration.

With the prolific work that has gone into improving and refining the transmission in the 2022 Iriz and Persona, why was this not publicised in promotional material at the cars’ launch? As it turns out, Proton has decided that attention was best focused upon the more apparent new features such as the new GKUI with its voice command functions, as well as to promote the advent of the Iriz Active as a new variant.

GALLERY: 2022 Proton Persona 1.6 Premium CVT



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